The fertility decline that Turkey has gone through in the last few decades is characterised by sharp regional inequalities, with western regions representing patterns akin to developed countries and those in the east resembling "third-world" countries, while central regions represent an in-between case. With the help of geographically weighted regression (GWR), this article is an attempt to set up a model of causal relationships that could account for the regional fertility differentials. The results indicate that the fertility decline is not a single and all-embracing process covering all regions. On the contrary, there are regions differentiated qualitatively from each other in terms of the underlying causes of the existing fertility leve...